RCAAP Repository

Red rice (Oryza saliva L.) is considered the most serious weed in rice crop in Rio Grande do Sul. Severaltechniques are employed to decrease its infestations on irrigated rice, among them, the use of minimum tillage. The objectiveof this research was to evaluate the effects of red rice chemical management on grain yield and agronomic characteristics ofirrigated rice in minimum tillage system, as well as to define the time in which such management can be performed. To reach thispurpose, a field experiment was conducted in 1996/97, with the following treatments: red rice desiccation periods (10, 6, and2 days before, and 2 days after rice sowing), non-selective herbicidas (sulfosate, at rates of 825 and 1650 g/ha, and paraquat at400 g/ha), plus controls without herbicide application (with and without start nitrogen fertilization), and systems of irrigatedrice sowing (in presence and in absence of red rice residues). The results showed that the presence of rice residues interferednegatively on grain yield of rice, especially when sowing occurred dose to herbicide application. Sulfosate, especially at thelow rate, caused reductions in most of the parameters evaluated.

Oryzophagus oryzae, the rice water weevil (RWW), an important insect pest in irrigated rice crop in Brazil, can reduce 10 to 30% the grain yield. The purpose of this study was to compare the efficiency of RWW chemical control by seed treatment, foliar spray or rice irrigation water treatment, using the more appropriated active ingredients, formulations and rates, to each insecticide application method. The seed treatment with carbossulfan TS (300 g/100 kg) or fipronil FS (50 and 75 g/100 kg), and foliar spray with fipronil WDG (60 and 80 g/ha), or lambdacyalothrin (10 glha)provided high larval control (92 to 99%) and avoided grain yield reduction (18 to 25%), equivalent to standard control method, based on carbofuran G (750 g/ha) applied directly on rice irrigation water. Fipronil G (60 and 80 g/ha) was significantly less efficient than granulated carbofuran. It was concluded that seed treatment and foliar spray, according to active ingredients used, are more efficient for RWW control than granular carbofuran applied directly on irrigation water.

The agronomic performance of ten Desmodium genotypes was evaluated in a trial carried out at Porto Velho,Rondonia. The experimental design was a radomized complete block with three replications. The following genotypes wereevaluated: five of D. ovalifolium (CIAT-350, CIAT-3666, CIAT-3673, CIAT-3774, and CIAT-3784), four of D. heterophilum(CIAT-349, CIAT-365, CIAT-3782, and CIAT-3791), and one of D. canum (CIAT-3522). During the rainy season, thegenotypes D. ovalifolium CIAT-350, CIAT-3784 and D. canum CIAT-3522 presented higher dry matter (DM) yields. Duringthe dry season, D. ovalifolium CIAT-3673, CIAT-350 and D. canum CIAT-3522 were the most productive genotypes. Thehighest crude protein contents were obtained by the genotypes D. heterophilum CIAT-349 and CIAT-365, which did not differfrom D. ovalifolium CIAT-3673. The genotypes of D. ovalifolium CIAT-3673, CIAT-350, and CIAT-3784 had higher phosphoruscontents. The highest calcium and magnesium contents were provided by D. ovalifolium CIAT-350 and D. heterophilumCIAT-3791, respectively, while higher potassium contents were obtained by D. canum CIAT-3522, D. heterophilum CIAT-3791 and D. ovalifolium CIAT-3774 genotypes. The higher in vitro dry matter digestibility coefficients were provided by D.heterophilum CIAT-3782 (50,3%), CIAT-349 (48,2%) and CIAT-3791 (47,7%). The most promising genotypes to obtainhigher forage yields with.better quality, were D. ovalifolium CIAT-350, CIAT-3673, and D. canum CIAT-3522.

Soil spatial variability of acidity factors (pH, Ca, Mg, Ca+Mg, AI, H+Al, sum of bases, cation exchangecapacity, and bases saturation) was studied in different soils and management systems, at two regions of Rio Grande do Sul -Brazil a) Eldorado do Sul, on a dark red podzolic soil, Kandiudult (conventional tillage, no-tillage, and chisel plow, in plots ofa soil management trial, and pasture), using a grid sampling of 1 x 1 m at the depths of 0-0,05 and 0,05-0,20 m; b) Passo Fundo,on a dusky red latosol, Hapludox (conventional tillage and no-tillage), and a dark red latosol, Hapludox (pasture), in agriculturalfarms, using a grid sampling of 10 x 10 m at the depths of 0-0,10, 0,10-0,20, and 0,20-0,30 m. Wheat yield variability wasstudied only in Passo Fundo by harvesting areas of 1 m 2 , at the same grid sampling. Soil properties followed a normaldistribution, in most of management systems and dephts. The lowest variability, evaluated by coefficients of variation, wasfound for pH and cation exchange capacity (CVs<10%), and the highest for Al (CVs>40%), with other properties placingintermediary position (10%<CV5 <40%). Among cultivated areas, no-tillage exhibited greater coefficients of variation, followedby minimum tillage and conventional tillage. Spatial correlation was found for pH, H+Al, and bases saturation in Eldorado doSul, whereas in Passo Fundo was found for all soil properties (with exception to H+Al and cation exchange capacity, inpasture) and for wheat yield on the management systems studied. No-tillage exhibited positive cross-correlation for wheatyield with Ca, with Mg, with Ca+Mg, with sum of bases, and with cation exchange capacity.

The objective of this work was to study the distribution of the statistics coefficient of variation (CV) and minimum significam difference (MSD) as a way to obtain the limits for quality control, in competition experiments of maize, rice, soybean, wheat, beans, barley, oat, triticale and sorghum. Data of 2017 cultivar competition assays, conducted in the state of Rio Grande do Sul, Brazil, from 1987 through 1995 were included. The CV and MSD values were submitted to the Lilliefors test. The class limits of these statistics were established based on the averages and variante of the variables tested. Using the analogous management criteria for conduction of the experiments, each assay was dismembered for each crop evaluated. We concluded that the diversity of management procedures employed in cultivar competition experiments adversely affects their quality control. This control must be performed according to the crop and management employed. No information is lost when CV and MSD classified as too high are disregarded.

The simulation of adverse environmental conditions and the monitoring of some key enzymes during the development of seedlings are able to orient the work of genetic improvement. Hence, this paper aims at: (a) detecting the presence of the enzyme alcohol dehydrogenase (ADH) in the seedling shoots developed under conditions of aerobiosis and of hipoxy; (b) relating the activities of the enzymes glutamate oxaloacetate transaminase (GOT) and malate dehydrogenase (MDH) to the availability of oxygen; and (c) comparing the growth of the seedling shoots with the activities of the enzymes studied. The treatments consisted of the temperatures of 20, 25 and 30oC under conditions of aerobiosis and of hipoxy, used during the germination and initial growth of seedlings of six genotypes of flooded rice. It was observed that the length of the seedling developed under aerobiosis at the temperatures of 25 and 30oC is superior than that of all other treatments. The enzyme ADH was only detected in seedlings developed under hipoxy and at temperatures higher than 20o C. The activity of the enzymes MDH and GOT in seedlings developed under either aerobiosis or hipoxy varies across temperatures. There is a higher level of activity of the enzyme GOT in seedlings of IRGA 417 and of the enzyme MDH in seedlings of IRGA 416, IRGA 417 and Bluebelle developed under aerobiosis than under hipoxy. 

Soil management systems differ in relation to topsoil mobilization and surface cover, resulting in differencesin soil physical attributes that can affect yield and environmental quality. Aiming the evaluation of some of these parametersand soil water dynamics in a winter crop, in southem Brazil, an experiment was conducted at the Estação ExperimentalAgronômica of UniverSidade Federal do Rio Grande do Sul, RS-Brazil, on a Red-yellow Podzolic soil under conventional tillageand no-tillage, for three years, both in a maize-oat/vetch rotation. Undisturbed soil samples were used to obtain bulk density,pore size distribution, soil water retention curve and hydraulic conductivity from the surface up to 0.70 m depth, determiningthe internai drainage at 0.60 m. Soil water dynamics, during the oat/vetch, cycle was monitored using tensiometers. Higherdifferences were observed at the depth of 0.20 m, where conventional tillage resülted in lower macroporosity and highermacroporosity, higher soil water retention, and a lower saturated and unsaturated hydraulic conductivity. These differences ledto a higher soil moisture content at 0.10, 0.20 and 0.30 m in conventional tillage, and a faster drainage at 0.60 m for the no-tillagetreatment. Therefore, it is concluded that significant physical changes have occurred in the soil after three years of implantationof the tillage systems, with higher water retention, under conventional tillage at 0.20 m, and drainage, under no-tillage.

This paper presents the history of the introduction into Brazil of the soybean crop, the development of theresearch, genetic improvement and of rhizobia technology. The oldest reference dates from 1882, and the first field observationsand trials were carried out in São Paulo around the tutu of the century. However, the crop really became established, initially,in the northwest of the state of Rio Grande do Sul in the 1930s..Research on the soya, including genetic improvement, beganin the south of Brazil, and in São Paulo. Introduced American varieties of soybean already had symbiotic capacity. There wasno application of mineral nitrogen in the experimental fields, and the seeds were inoculated with rhizobia. The activities onrhizobia technology were developed mainly in the states of Rio Grande do Sul and São Paulo. In the first one, since 1950, thework was based mainly on selection of improved strains, production of inoculants and research on soil limiting factors. Thestrains developed and released in Rio Grande do Sul were, up to 1992, the only balis of the inoculants produced in the Country.Important factors for the expansion, productivity and production of the soybean crop were: efficient Rhizobium strains, largescale inoculant production, responsive plant varieties and correction of soil limiting factors.

Twenty two swine farms in Southwest of Paraná State, Brazil, were evaluated during the summer of 1991. In each herd, at least six sows and her litters were evaluated from the birth up to weaning by four objective variables (diarrhea in the suckling, mortality rate, weight variation coefficient at weaning and daily average weight gain in the period), and sixteen explanatory variables were studied (daily thermal amplitude, % area of the windows in the plant, pen's area, corporal status  of the sow, creep presence, farrowing assistance, omphalitis presence, internal minimal temperature in the building, litter size at birth, colibacillosis vaccination, number of piglets per pen, collective suckling, roof presence in the building, intestinal parasites presence and sanitary break utilization. The variables were evaluated by ECOSUI program developed by Embrapa Suínos e Aves. The main risk factors observed, present in more than 95% of the farms were: high daily thermal amplitude, sanitary break absence, intestinal parasites presence in sows and her litters, colibacilosis vaccination absence. The results indicate the presence of risk factors in the farms studied which reduce the piglets performance.

The effects of early weaning (EW) and temporary calf remova' (TCR) on beef cattle cows and their calvos wereevaluated. Also were assessed: the weight at beginning of the breeding season (WBBSc), the weight at beginning of the earlyweaning (WEWc), the weight at the end of breeding season (WEBSc), the final weight (FWc), the average daily gain (ADGc),and the pregnancy rate (PR), for the cows. It was evaluated the early weaning weight (EWWcalf), the weight at the end of thetrial (Ewcalf), and the average daily gain (ADGcalf), for the calves submitted to EW or TCR. The breeding season started at 12/01/97 and finished at 02/28/98. The EW was measured at 01/03/98, and the TCR at 12/02/97, 01/03/98, and 02/03/98. WBBSc,WEWc, WEBSc, and FWc were 427.0 and 446.9 kg, 432.9 and 343.9 kg, 464.0 and 452.4 kg, 472.5 and 435.5 kg, for the cowssubmitted to EW and TCR, respectively, with no significance (P>0.05). However, the ADGc, from 12/01/97 to 02/28/98, was0.421 and 0.059 kg/day to the EW and TCR, respectively (P< 0.01). The PR was 90%, for the EW group, and 23.8 %, for theTCR group (P<0.01). The Ewcalf was 143.1 and 172.1 kg, for the EW and TCR groups, respectively, (P<0.01). The ADGcalfwas 0.237 and 0.532 kg/day (P<0.01), respectively, for calves submitted to EW or TCR group. The cows submitted to EWshowed a higher PR and ADGc. However, the calves in the TCR group showed higher Ewcalf and AVDcalf than the EW calves.

Antibodies to Bovine Leukemia Virus (BLV) were determincd by the agar gel immunodiffusion test in serum samples from dairy cattle imported from Uruguay to Brazil. From 19,774 samples tested during 1992-1997, 3,225 (16.30 %) had antibodies. These results suggest the necessity to import only negative cattle to BLV and to implant control measures in Brazil. 

The pre-germinated rice growing system demands genotypes with a higher capacity of initial development in an anaerobic environment. Having in mind the need for better knowing the characteristics of the cultivars El Paso 144, BR IRGA 409, BR IRGA 410, IRGA 416, IRGA 417 and Bluebelle, this paper reports a comparative study of the enzymatic activity of glutamate oxaloacetate transaminase (GOT), esterase (EST), and malate dehydrogenase (MDH), in the rice seedling shoots through electrophoresis. The treatments consisted in germination and development of the seedlings during 14 days at the temperatures of 20, 25 and 30oC under both aerobic and anaerobic conditions. The analysis of the electrophoresis gels leads to conclude that: a) The IRGA 417 seedlings stands out against the other cultivars because of its higher level of activity of the enzymes studied under the anaerobic treatment at the temperature of 20o C; and b) The great variability found in the enzymatic systems studied for the different genotypes and treatments used allow to recommend that studies of genotype x environment interaction use biochemical systems, in order to assist in the search for genotypes that are able to overcome environmental stress. 

This trial was conducted to determine the value of soybean hulls as a replacement for com grain in finishing beef heifers diets. Dietary treatments consisted of four substitution levels (0, 25, 50 and 75 %) of com grain by whole soybean hulls. Hundred and eight beef caule heifers were used in a randomized complete block design, with four treatments, three replications, with nine animais in each pen. Animais were fed twice a day with a com silage based diet, plus whole soybeans, mineral supplement and a variable amount of ground com grain and soybean hulls. No differences were detected among levels of soybean hulls substituting com grain upon final weight, daily weight gain or feed conversion.

This essay was established at the Fundação Estadual de Pesquisa Agropecuária Experimental station in Maquine in the northeastem Rio Grande do Sul state coastland, Brasil. From august 1997 to october 1999 were evaluated in a pineaple experiment the effect of soil management techniques (conventional, strip- tillage and no-tillage, planting tecniques (furrow and spear), on biomass yield and its nutrient contents. Fruit quality and productivity were also evaluated in this pineaple cv. pérola second harvest. Results showed that soil management techniques did not affect biomass production and nutrient concentration on pineaple leaves. In the conventional tillage, biomass productivity (green and dry) and that of fruits was 45.6; 7.4; 14.4 t/ha and its contents of N; P; K; Ca and Mg amounted 99; 10; 238; 10 and 10 kg/ha respectively. Mantained the due proportions of biomass yield and its nutrients in the higher technological levei (MODEL, 1999) the fertilization needs would be 587 kg of N and 946 kg of K O. Productivity and percentage of harvest in conventiohal ti Ilage (14.35 t/ha and 51.2 %) were higher than in no :tillage (8.61 t/ha and 31.2%) respectively. Length of fruit and crown diameter in the conventional-tillage were higher than in no-tillage, but fruit lenght and total degree of soluble solids showed to be not affected by treatments.

Considering the increasing application of horticultural substrates and the fact that soil is still usedby producers in their mixes, it was conduced an experiment aiming to verify the viability of a Haplumbrept soil as acomponent of horticultural substrate mixes, along with organic conditioners. The soil was chosen due to their hightotal porosity, high level of organic matter and low capacity to agricultural use. In the experiment, the soil wasmixed, in volumetric proportion 1:1, with water hyacinth [Eichhornia crassipes (Mart.) Solms], rest of sugar cane,sawdust of Pinus sp and carbonized rice hulls. The mixes were submitted to physical (bulk density, total porosity,water availability and aeration) and chemical characterization (pH and total soluble salt concentration). Except tothe mix with sawdust, all mixes improved physical characteristics, providing lower bulk density, higher porosity andmore water availability. All conditioners, but water hyacinth, increased the mixes pH, and all of then increasedsoluble salts contents.

It was determined probability to occur equal or superior pluvial precipitation 100% and 60% of themaximum evapotranspiration (ETm) of the common bean, in different sub period and sowing dates, for threelocalities in Rio Grande do Sul State, Brazil. With the daily pluvial precipitation data, determined the accumulationof pluvial precipitation (TPP) in each sub period, sowing date and locality. The adjustment of the data of TPP wasevaluated in each sub period, sowing date and locality, to the distributions normal and gama, using Lilliefors’ testfor first and Kolmogorov-Smirnovs’ test for second. It was verified that the probability the pluvial precipitation beequal or superior of the ETm for common bean in complete cycle were minor in Julio de Castilhos, intermediary inCruz Alta and superior in Passo Fundo. However, between studies localities, Passo Fundo is the local of minorproduction risk. The lesser probabilities had occurred during the sub periods most critical of the culture, understoodbetween the beginning of the flowering and the physiological maturation, when the probabilities are lesser than50%, considering the total ETm. The three sowing dates considered, the lesser probabilities during the completecycle of the culture occurred in October and November, being that in the critical period, the sowing of Septemberpresented the higher probability

The experimental work was carried out at the Estação Experimental da Faculdade de Agronomia, UFRGS, in Eldorado do Sul, Rio Grande do Sul, Brazil. The objective was to evaluate the effect of fertilizer treatments (with and without N, P and K) and lime leveis (0; 1,5 and 3,0 ton/ha) on a Plintossolo, on the yield and botanical composition of a nature pasture sodseeded with white clover (Trifolhan repens L.). The climate is Cfa, according to Kaeppen's classification. The experimental design was a split-plot arranged in randomized block with three replications. The fertilization on the first year was 22,5 kg N/ha, 180 kg P205/ha and 120 kg K 20/ha. On the second and third year the amounts were of 90 kg P 205/ha and 48kg K20/ha. On the fourth year were of 24 kg N/ha, 84 kg P205/ha e 63 kg K20/ha. Fertilization with N, P and K increased the forage dry matter yield and changed the botanical composition of the natural pasture. Such variables were also affected by the year .

An analysis of genotype x environment interaction was perfomed on grain yields of twenty-fourgenotypes of bean (Phaseolus vulgaris L.) grown at five different locations in Rio Grande do Sul. The stabilityparameters were estimated by the linear regression model of EBERHART & RUSSEL (1966). In addition, theenvironmental index of the model was obtained through wheather variables and disease index. The best estimatorof the environment was the usual environmental index, whereas the weather variables and disease index failled toprovide a good estimation.

This study had as objective evaluates the potential behavior of eight cultivars of melon plants, hybrid and varieties, seeking your indication for cultivation in polyethylene greenhouse, in the region of the Serra do Nordeste of Rio Grande do Sul State, Brazil. The experimental design was randomized blocks, with three replications for treatment. The yields varied from 8,22 kg m-2 to 5,20 kg m-2.The cultivars Galeão, C.A.C. and Jumbo were the more fruitfull, while the Gaúcho cultivar was the most productive in function of the largest medium weight of fruit, 1,412 kg. C.A.C. cultivar presented the smallest fruit size, 0,798 kg. The standardization of fruits for the size showed the need to establish, through pruning fruits, the number of fruits ideal for plant for each variety. The largest uniformity in the maturation of fruits was presented by cultivar RML-2704.

Aiming to delimit areas showing climate aptitude for growing com, an agroclimatic zoning based on growing degrce-days and water deficit as agroclimatic indexes, at different sowing dates, was generated for the State of Rio Grande do Sul, Brazil. The zoning was established for sowing dates 8/1, 9/1, 10/1, 11/1,12/1, and 1/1, and six maps (1:750,000), which are presented in a reduced forre in this papei, were obtained. The zoning areas were classified as Preferential I and II. Tolerable. Marginal, and Not Recomended for com. Planalto, Serra do Nordeste, Serra do Sudeste, and Alto Vale do Uruguai are the regions showing higher potential for com in the state. Additionally, Médio and Baixo Vale do Uruguai, Missões, Depressão Central, Litoral Sul, and Campanha regions, though also showing potential for com, have the highest values of water deficit and, by using irrigation, are clssified through the temperature index. The main limitation to high com yields in the state is linked to water deficit that normaly occurs in southwestern and southeastern state arcas and in part of Depressão Central region in 9/1 to 1/1 sowing dates. Low temperaturas and frost occurrence are the most limiting factors in the sowings centered in 8/ 1. The results obtained show that climate aptitude for com in Rio grande do Sul varies according to the sowing date and region, evidencing the importante of carrying out the zoning by sowing dates.